The Duchess of Devonshire, née Deborah Mitford Deborah Cavendish (AKA the The Dowager Duchess of Devonshire), is the youngest and last surviving member of the six Mitford sisters, and at 90 is publishing her memoirs Tweet The Duchess of Devonshire at home on the edge of the Chatsworth estate in Derbyshire Photograph: Christopher Thomond/Guardian The Mitford family (l-r top) Lady Redesdale, Nancy, Tom and Lord Redesdale, (middle) Diana and Pamela, (bottom) Unity, Jessica and Deborah. The sisters were educated at home, because their mother didn't believe in exams, and Deborah spent most of her time hunting and skating Photograph: BBC 1st January 1941: The young Deborah Mitford, Dowager Duchess of Devonshire. When she married Andrew Cavendish, as the second son he did not expect to become duke, but his older brother was killed in the second world war Photograph: PA The five other Mitford sisters - Jessica, Nancy, Diana, Unity and Pamela - in 1935 Photograph: Harpercollins Society Women, 1938: the Hon Pamela Herman Hodge (left), the Hon Deborah Mitford (centre) and Lady Margaret Ogilvy at a point-to-point race meeting Photograph: Hulton Archive Deborah Mitford awaiting the arrival of her sister Unity, from Germany in 1940 Photograph: Hulton Archive/Getty Images Deborah attending at a banquet given by the Royal Society of St George, in 1954 Photograph: Getty Images An aerial view of Chatsworth House in Derbyshire. Until the death of the 11th duke in 2004, the duchess lived in the house. Afterwards she moved about a mile away to a vicarage on the edge of the estate Photograph: Christopher Furlong/Getty Images The Duchess of Devonshire, at Chatsworth, sitting on garden furniture made at the estate workshops in the 1970s Photograph: Popperfoto The Duchess of Devonshire out shooting in 1980 Photograph: Getty Images The Duke and Duchess of Devonshire at Buckingham Palace in London. The duchess was honoured by the Queen by being made a Dame Commander of The Royal Victorian Order Photograph: Fiona Hanson/PA The Duke and Duchess of Devonshire celebrating their Golden wedding with 1000 couples at Chatsworth Photograph: Steve Etherington/Empics The duchess with her beloved chickens in the 1990s Photograph: Christopher Simon Sykes/Getty Images The Duchess of Devonshire at her home since 2004, the Old Vicarage at Edensor Photograph: Christopher Thomond/Guardian